Portable resistance load



June 2, 1942. w. J. LARSON 3 PORTABLE RESISTANCE LOAD Filed Aug. 27, 1941 J 5 I Fly 4 //VS(/L,4T/0/V 7 5. 1' I 5 l0 5 Elllill Dill-3 mm Elllill llzsllla 25 2 mm mm llilllli Patented June 2, 1942 PORTABLE RESISTANCE LOAD Werner J. Larson, West Hartford, Conn, assignor to The States Company, Hartford, Conn., a corporation of Connecticut Application August 2'7, 1941, Serial No. 408,495

7 Claims.

This invention relates to a portable resistance load which is particularly adapted for use in testing electric meters.

The object of the invention is the provision of an artificial load comprised of a plurality of spaced resistanse units of different predetermined capacities and terminals for connecting line conductors in various combinations with the units, which is light in weight and is capable of being instantly collapsed into a small space for transportation from locality to locality and quickly expanded for service, the assembly being such that when collapsed the several resistance units fold together and are completely disconnected from the terminals or the line conductors and when expanded the units are widely separated and automatically connected with the terminals.

Fig. 1 shows a front elevation of the resistance.

Fig. 2 is a View looking at one side of the resistance when it is expanded.

Fig. 3 is a top view of the expanded resistance.

Fig. 4 is a top view of the resistance partially collapsed.

Fig. 5 is, on larger scale, a section taken on dotted line 55 on Fig. 2 illustrating the electrical connections between resistance units and terminals, as when the resistance is expanded for service.

Fig. 6 is a similar view with the electrical connections disengaged as when the resistance is collapsed.

In the embodiment of the invention illustrated the resistance units, of which six are shown, are composed of grids of woven vertical strands of insulation 1, preferably asbestos, and horizontal loops of wire 2, of alloyed metals which will offer the desired predetermined resistances for the several units. The grids are attached to and stretched between parallel upper and lower horizontally extending rods 3, that at the back are connected by vertical rods 4 and at the front by vertical strips 5. Secured to the strips 5 and suitably insulated therefrom are conducting contacts 6 and at various heights taps I are led from the resistance wires and connected to the contacts 6. In the construction shown the front ends of the upper and lower rods 3 are pivotally connected with horizontal strips 8, and at the rear the rods 4 are pivotally connected with horizontal strips 9. The supporting frame is comprised of a front plate In with internal flanges II, and a rear plate [2 with internal flanges I3. 65

The strips 8 and 9 are secured to these flanges of the front and rear plates. As a result of this construction the resistance units and supporting frame are so hinged together that the plates may be opened from and closed toward each other with a parallel movement. When the plates are closed the units are folded flatwise closely together and when the plates are opened from each other the resistance units are unfolded and extend front and back parallel with each other and suitably spaced apart. At one side of the supporting frame a plate I4 is hinged to the front and back plates in a manner similar to the hinging of the resistance units. This plate folds with the resistance units and affords them protection. The side plate M has a button 15 which may be turned over a flange [6 on the back plate for fastening the structure when it is open and in condition for use. At the other side of the frame there may be a similar protecting plate, this however is omitted from the drawing for the purpose of more clearly exposing the construction.

Attached to the face of the front plate is an insulating panel I! upon which are secured rows of conducting terminals l8 having ears 19 adapted to be engaged by clips at the ends of line wires. Secured to the inside of the front plate and suitably insulated therefrom, opposite and electrically connected with each terminal is a conducting spring finger 20. These spring fingers 2i) are so positioned that when the resistance is unfolded for use they will be engaged by the conducting contacts 6 (Fig. 5) to which the taps I lead from the wires 2 of the several resistance units and each terminal will be electrically connected with a resistance unit. When the resistance is folded the contacts 6 are disengaged from and carried away from the spring fingers 20 (Fig. 6) so that there will be no electrical connection between the resistance units and the terminals on the front of the panel.

In the design illustrated the terminals l8 are positioned on the panel in four horizontal rows and four vertical rows. The horizontal rows of terminals are marked respectively 0, I20, 208, and 246 and the vertical rows of terminals are marked respectively I, 5 and 5, indicating the voltage and ampere calibrations of the resistance loops at the points to which the several terminals are tapped. Ears of terminals and l are arranged adjacent so that they may be clipped together to function for 1 /2 ampere current, and ears of the terminals 5-5 are arranged adjacent to function for 10 ampere current.

In using the load the plates are drawn apart and the resistance units unfolded, which action closes the electrical paths between all of the units and the respective terminals. One line terminal, depending upon the amperage at which it is desired to make the test, is then connected to the indicated resistance terminal in the top, row, and the other line terminal is connected to the resistance terminal vertically below in the row having the indicated voltage. For exampleshould the test be a.-120 v., one line terminal is clipped to the resistance terminal 2! and the other line terminal is clipped to the resistance terminal 22. For ,42 a.-208 v. the line terminals would be clipped to resistance terminals 2| and 2 3. For a.-240 v. the line terminals would be clipped to resistance terminals 21 and 24. For 1 ampere the line terminals are connected to the resistance terminals 25 and either of the terminals 26, 21 or 28 depending upon the voltage. For 1 ampere one line terminal is connected to bridge the resistance terminals 2l25 and the other line terminal is connected to bridge the resistance terminals 22-46, 23-21 or 24-48 depending upon the voltage. When the test is completed the line terminals are withdrawn and the frame plates pushed together folding the resistance units into a small space and at the same time opening all electrical connection between the resistance units and the resistance terminals.

This resistance is particularly adapted for controlling the current in testing watt-hour meters and relays under light loads and full loads away from the laboratory and when collapsed is compact and convenient to carry from place to place.

The invention claimed is:

l. A portable resistance load which comprises a collapsible supporting frame, a plurality of resistance units hinged between walls of said frame, said units folding together flatwise when the frame is collapsed and unfolding and extending parallel with each other at spaced distances apart when the frame is expanded, conducting terminals fixed on said frame, and conducting means connected to and moved by the movements of said units, said conducting means being positioned to be carried into contact with said terminals as the frame is expanded and carried out of engagement with said terminals as the frame is collapsed.

2. A portable resistance load which comprises a collapsible supporting frame, a plurality of resistance units hinged between walls of said frame, said units folding together fiatwise when the frame is collapsed and unfolding and extending parallel with each other at spaced dis tances apart when the frame is expanded, a panel of insulating material on said frame, conducting terminals on said anel, and conducting means connected with said units, said means being mounted on and carried by said units into contact with said terminals as the frame is expanded and carried out of engagement with said terminals as the frame is collapsed.

3. A portable resistance load which comprises a collapsible supporting frame, a plurality of resistance units hinged between walls 'of said frame, said units folding together flatwise when the frame is collapsed and unfolding and extending parallel with each other at spaced distances apart when the frame is expanded, a panel of insulating material on said frame, conducting terminals on the front of and extending through said panel, yielding conducting contacts connected with said terminals back of said panel, and conducting contacts connected to and carried by said units into engagement with said yielding contacts when the frame is expanded and carried by said units out of engagement with said yielding contacts when the frame is collapsed.

4. A portable resistance load which comprises a front plate, a back plate, a plurality of resistance units loosely linking said plates in parallel relation, said units folding together flatwise when said plates are moved toward each other and unfolding and extending parallel with each other at spaced distances apart when said plates are moved from each other, a panel on said front plate, conducting terminals mounted on said panel, and conducting means connected to and carried by said units, said means being positioned to be engaged with said terminals as the plates are moved from each other and to disengage from said terminals as the plates are moved toward each other.

5. A portable resistance load which comprises a collapsible supporting frame, a plurality of vertically positioned resistance units hinged between walls of said frame, said units folding together fiatwise when the frame is collapsed and unfolding and extending parallel with each other at spaced distances apart when the frame is expanded, a panel on said frame, conducting terminals spaced in vertical rows on said panel,

and conducting contacts carried by said units,

said contacts being spaced in vertical rows and tapped to said units at different vertical localities, the contacts of each row being positioned to engage with a row of said terminals by the expansion of the frame and disengaged from said terminals by the collapse of the frame.

6. A portable resistance load which comprises a collapsible supporting frame, a plurality of resistance units of different capacities hinged between walls of said frame, said units folding together flatwise when the frame is collapsed and unfolding and extending parallel with each other at spaced distances apart when the frame is expanded, a panel on said frame, conducting terminals spaced in vertical and horizontal rows on said panel, and a plurality of conducting contacts mounted to be moved by and tapped at different localities to each resistance unit, said contacts being positioned vertically in line with and spaced vertically the same as the vertical rows of terminals and positioned horizontally in line with and spaced horizontally the same as the horizontal rows of terminals, so that as the units to which the contacts are connected are unfolded each contact is caused to engage with a terminal and as the units are folded all of the contacts are disengaged from all of the terminals.

'7. A portable resistance load which comprises a collapsible supporting frame, a plurality of resistance units of different capacities hinged between walls of said frame, said units closing together flatwise when the frame is collapsed and opening and extending parallel with each other at spaced distances apart when the frame is expanded, conducting contacts carried by and tapped to said units at different points, and conducting terminals on said frame in position to be engaged by said contacts when said units are in opened relation and spaced from said contacts when said units are in closed relation.

WERNER J. LARSON. 

